'use strict';

// Do this as the first thing so that any code reading it knows the right env.
process.env.BABEL_ENV = 'production';
process.env.NODE_ENV = 'production';

// Makes the script crash on unhandled rejections instead of silently
// ignoring them. In the future, promise rejections that are not handled will
// terminate the Node.js process with a non-zero exit code.
process.on('unhandledRejection', err => {
	throw err;
});

// Ensure environment variables are read.
require('../config/env');


const path = require('path');
const chalk = require('react-dev-utils/chalk');
const fs = require('fs-extra');
const webpack = require('webpack');
const configFactory = require('../config/webpack.config');
const paths = require('../config/paths');
const checkRequiredFiles = require('react-dev-utils/checkRequiredFiles');
const formatWebpackMessages = require('react-dev-utils/formatWebpackMessages');
const printHostingInstructions = require('react-dev-utils/printHostingInstructions');
const FileSizeReporter = require('react-dev-utils/FileSizeReporter');
const printBuildError = require('react-dev-utils/printBuildError');

const measureFileSizesBeforeBuild =
  FileSizeReporter.measureFileSizesBeforeBuild;
const printFileSizesAfterBuild = FileSizeReporter.printFileSizesAfterBuild;
const useYarn = fs.existsSync(paths.yarnLockFile);

// These sizes are pretty large. We'll warn for bundles exceeding them.
const WARN_AFTER_BUNDLE_GZIP_SIZE = 512 * 1024;
const WARN_AFTER_CHUNK_GZIP_SIZE = 1024 * 1024;

const isInteractive = process.stdout.isTTY;

// Warn and crash if required files are missing
if (!checkRequiredFiles([paths.appHtml, paths.appIndexJs])) {
	process.exit(1);
}

// Generate configuration
const config = configFactory('production');

// We require that you explicitly set browsers and do not fall back to
// browserslist defaults.
const { checkBrowsers } = require('react-dev-utils/browsersHelper');
checkBrowsers(paths.appPath, isInteractive)
	.then(() => {
		// First, read the current file sizes in build directory.
		// This lets us display how much they changed later.
		return measureFileSizesBeforeBuild(paths.appBuild);
	})
	.then(previousFileSizes => {
		// Remove all content but keep the directory so that
		// if you're in it, you don't end up in Trash
		fs.emptyDirSync(paths.appBuild);
		// Merge with the public folder
		copyPublicFolder();
		// Start the webpack build
		return build(previousFileSizes);
	})
	.then(
		({ stats, previousFileSizes, warnings }) => {
			if (warnings.length) {
				console.log(chalk.yellow('Compiled with warnings.\n'));
				console.log(warnings.join('\n\n'));
				console.log(
					`\nSearch for the ${
						chalk.underline(chalk.yellow('keywords'))
					} to learn more about each warning.`
				);
				console.log(
					`To ignore, add ${
						chalk.cyan('// eslint-disable-next-line')
					} to the line before.\n`
				);
			} else {
				console.log(chalk.green('Compiled successfully.\n'));
			}

			console.log('File sizes after gzip:\n');
			printFileSizesAfterBuild(
				stats,
				previousFileSizes,
				paths.appBuild,
				WARN_AFTER_BUNDLE_GZIP_SIZE,
				WARN_AFTER_CHUNK_GZIP_SIZE
			);
			console.log();

			const appPackage = require(paths.appPackageJson);
			const publicUrl = paths.publicUrl;
			const publicPath = config.output.publicPath;
			const buildFolder = path.relative(process.cwd(), paths.appBuild);
			printHostingInstructions(
				appPackage,
				publicUrl,
				publicPath,
				buildFolder,
				useYarn
			);
		},
		err => {
			const tscCompileOnError = process.env.TSC_COMPILE_ON_ERROR === 'true';
			if (tscCompileOnError) {
				console.log(
					chalk.yellow(
						'Compiled with the following type errors (you may want to check these before deploying your app):\n'
					)
				);
				printBuildError(err);
			} else {
				console.log(chalk.red('Failed to compile.\n'));
				printBuildError(err);
				process.exit(1);
			}
		}
	)
	.catch(err => {
		if (err && err.message) {
			console.log(err.message);
		}
		process.exit(1);
	});

// Create the production build and print the deployment instructions.
function build(previousFileSizes) {
	// We used to support resolving modules according to `NODE_PATH`.
	// This now has been deprecated in favor of jsconfig/tsconfig.json
	// This lets you use absolute paths in imports inside large monorepos:
	if (process.env.NODE_PATH) {
		console.log(
			chalk.yellow(
				'Setting NODE_PATH to resolve modules absolutely has been deprecated in favor of setting baseUrl in jsconfig.json (or tsconfig.json if you are using TypeScript) and will be removed in a future major release of create-react-app.'
			)
		);
		console.log();
	}

	console.log('Creating an optimized production build...');

	const compiler = webpack(config);
	return new Promise((resolve, reject) => {
		compiler.run((err, stats) => {
			let messages;
			if (err) {
				if (!err.message) {
					return reject(err);
				}

				let errMessage = err.message;

				// Add additional information for postcss errors
				if (Object.prototype.hasOwnProperty.call(err, 'postcssNode')) {
					errMessage +=
            `\nCompileError: Begins at CSS selector ${
            	err['postcssNode'].selector}`;
				}

				messages = formatWebpackMessages({
					errors: [errMessage],
					warnings: [],
				});
			} else {
				messages = formatWebpackMessages(
					stats.toJson({ all: false, warnings: true, errors: true })
				);
			}
			if (messages.errors.length) {
				// Only keep the first error. Others are often indicative
				// of the same problem, but confuse the reader with noise.
				if (messages.errors.length > 1) {
					messages.errors.length = 1;
				}
				return reject(new Error(messages.errors.join('\n\n')));
			}
			if (
				process.env.CI &&
        (typeof process.env.CI !== 'string' ||
          process.env.CI.toLowerCase() !== 'false') &&
        messages.warnings.length
			) {
				console.log(
					chalk.yellow(
						'\nTreating warnings as errors because process.env.CI = true.\n' +
              'Most CI servers set it automatically.\n'
					)
				);
				return reject(new Error(messages.warnings.join('\n\n')));
			}

			return resolve({
				stats,
				previousFileSizes,
				warnings: messages.warnings,
			});
		});
	});
}

function copyPublicFolder() {
	fs.copySync(paths.appPublic, paths.appBuild, {
		dereference: true,
		filter: file => file !== paths.appHtml,
	});
}
